This invention has to do with cookware lubricant compositions based on lecithin. More particularly the invention is concerned with water-in-oil emulsion cookware lubricants stable against freeze-thaw cycles typically encountered in wintertime shipment of product and which is hydrolysis stable as well.
As such, the invention relates to improvements in lecithin based cookware lubricant products generally of the type comprising lecithin in a delivery system for thin film application, as a fluid, onto the surface to be lubricated. Commencing perhaps with the invention disclosed in U.S. Pat. No. 2,796,363 to Lalone, the thin film application of fluidized lecithin has been popularized as a healthful, low cost, natural and cholesterol-free way to obtain lubricity on cooking surfaces especially frying pans. In the Lalone patent, in companion U.S. Pat. No. 3,038,816 to Drell and Rubin and in its commercial counterpart PAM, the lecithin or equivalent ester is dissolved in a fluorocarbon propellant; the solution upon being sprayed volatilizes off the propellant leaving a fine mist of lecithin coming out of solution onto the pan surface being treated.
The increasing cost of fluorocarbon propellants, in dollars owing to the petrochemical supply situation, and in social terms because of supposed impact upon the earth's ozone layer of released fluorocarbons, has caused manufacturers to look to alternatives to fluorocarbon solutions of lecithin. One effort is recorded in U.S. Pat. No. 3,661,605 to Rubin and Meyerhoff, wherein a specific hydroxylated form of lecithin was found to be emulsifiable in water and to be propellable with nonfluorocarbon propellants. No commercial use of the Rubin-Meyerhoff is known to me.
Another worker in the art patented a water-in-oil emulsion system which obtained good dispersion of lecithin without use of fluorocarbons, at substantially lower cost and with other attendant economic and social benefits described in U.S. Pat. No. 3,896,975 to Follmer. The product has been commercially sold under the trademark PAN PAL.
It has been found that upon exposure to freezing temperatures, sometimes followed by a warmer condition, and then colder as may be encountered in winter shipments of product in the continental Midwest and Northwest, that a breakdown of the lecithin water-in-oil emulsion is experienced, limiting the utility of the product and causing consumer dissatisfaction based on clogging of delivery nozzles, abnormal appearance of the product, odor or inadequacy of lubricity.